How to add multiple choices (expressions) dynamically to Choice?

Hi, it's  not clear to me what you are trying to achieve and which is the blocker, can you add some information?

Check this out .

{
  a!localVariables(
    /* Defines whether or not to collapse the side nav */
    local!collapseNav: false,
    /* The selected navigation section */
    local!activeCollapsibleNavSection: 1,
    /* The navigation sections */
    local!collapsibleNavSections: {
      a!map(name: "Workspace", icon: "briefcase"),
      a!map(name: "Tasks",     icon: "tasks"),
      a!map(name: "Requests",  icon: "paper-plane"),
      a!map(name: "Calendar",  icon: "calendar"),
      a!map(name: "My Time",   icon: "clock-o"),
      a!map(name: "Expenses",  icon: "money")
    },
    {
      a!columnsLayout(
        columns: {
          a!columnLayout(
            contents: {
              a!forEach(
                items: local!collapsibleNavSections,
                expression: if(
                  local!collapseNav,
                  {
                    a!richTextDisplayField(
                      value: {
                        a!richTextIcon(
                          icon: fv!item.icon,
                          caption: fv!item.name,
                          link: a!dynamicLink(
                            value: fv!index,
                            saveInto: local!activeCollapsibleNavSection
                          ),
                          linkStyle: "STANDALONE",
                          color: if(
                            fv!index = local!activeCollapsibleNavSection,
                            "ACCENT",
                            "SECONDARY"
                          ),
                          size: "LARGE"
                        )
                      },
                      align: "CENTER",
                      accessibilityText: if(
                        fv!index = local!activeCollapsibleNavSection,
                        fv!item.name & " " & "selected",
                        ""
                      )
                    )
                  },
                  a!cardLayout(
                    contents: a!sideBySideLayout(
                      items: {
                        a!sideBySideItem(
                          item: a!richTextDisplayField(
                            labelPosition: "COLLAPSED",
                            value: a!richTextIcon(
                              icon: fv!item.icon,
                              color: "SECONDARY",
                              size: if(local!collapseNav, "LARGE", "MEDIUM")
                            ),
                            align: "LEFT"
                          ),
                          width: "MINIMIZE"
                        ),
                        a!sideBySideItem(
                          item: a!richTextDisplayField(
                            labelPosition: "COLLAPSED",
                            value: a!richTextItem(
                              text: fv!item.name,
                              color: "ACCENT",
                              size: "MEDIUM",
                              style: if(
                                fv!index = local!activeCollapsibleNavSection,
                                "STRONG",
                                "PLAIN"
                              )
                            )
                          ),
                          showWhen: not(local!collapseNav)
                        )
                      },
                      alignVertical: "MIDDLE"
                    ),
                    link: a!dynamicLink(
                      value: fv!index,
                      saveInto: local!activeCollapsibleNavSection
                    ),
                    style: if(
                      fv!index = local!activeCollapsibleNavSection,
                      "ACCENT",
                      "NONE"
                    ),
                    showBorder: false,
                    accessibilityText: if(
                      fv!index = local!activeCollapsibleNavSection,
                      fv!item.name & " " & "selected",
                      ""
                    )
                  )
                )
              ),
              a!richTextDisplayField(
                value: a!richTextIcon(
                  icon: if(
                    local!collapseNav,
                    "angle-double-right",
                    "angle-double-left"
                  ),
                  caption: if(
                    local!collapseNav,
                    "Expand navigation bar",
                    "Collapse navigation bar"
                  ),
                  link: a!dynamicLink(
                    value: not(local!collapseNav),
                    saveInto: local!collapseNav
                  ),
                  linkStyle: "STANDALONE",
                  color: "SECONDARY",
                  size: "MEDIUM"
                ),
                align: "CENTER"
              ),
              /* This card is used to set a minimum height on the column so that the *
               * divider takes up more screen space when there is minimal content.   *
               * Once content is added to the main column, this can be removed.      */
              a!cardLayout(
                height: "TALL",
                showWhen: not(a!isPageWidth("PHONE")),
                showBorder: false
              )
            },
            width: if(local!collapseNav, "EXTRA_NARROW", "NARROW")
          ),
          a!columnLayout(
            contents: {
              /* Conditionally display selected navigation section.       *
               * Sections are created individually here because they will *
               * have varying contents, so if you change the list in      *
               * local!collapisbleNavSections, you will need to make sure *
               * the list of sections here is the correct length.         */
              choose(
                local!activeCollapsibleNavSection,
                a!sectionLayout(
                  label: index(
                    local!collapsibleNavSections.name,
                    local!activeCollapsibleNavSection,
                    ""
                  ),
                  contents: {}
                ),
                a!sectionLayout(
                  label: index(
                    local!collapsibleNavSections.name,
                    local!activeCollapsibleNavSection,
                    ""
                  ),
                  contents: {}
                ),
                a!sectionLayout(
                  label: index(
                    local!collapsibleNavSections.name,
                    local!activeCollapsibleNavSection,
                    ""
                  ),
                  contents: {}
                ),
                a!sectionLayout(
                  label: index(
                    local!collapsibleNavSections.name,
                    local!activeCollapsibleNavSection,
                    ""
                  ),
                  contents: {}
                ),
                a!sectionLayout(
                  label: index(
                    local!collapsibleNavSections.name,
                    local!activeCollapsibleNavSection,
                    ""
                  ),
                  contents: {}
                ),
                a!sectionLayout(
                  label: index(
                    local!collapsibleNavSections.name,
                    local!activeCollapsibleNavSection,
                    ""
                  ),
                  contents: {}
                )
              )
            }
          )
        },
        spacing: "SPARSE",
        showDividers: true
      )
    }
  )
}