gistfile1.txt

 <Field DisplayName="ChoiceField" FillInChoice="FALSE" Format="Dropdown" Name="ChoiceField" Title="ChoiceField" Type="MultiChoice" ID="{bfc3a23a-832b-4c4a-b9e3-254e3cb7917a}" SourceID="{fd155260-83fa-440e-85c7-ff9026d1b2ff}" StaticName="ChoiceField" ColName="ntext6" RowOrdinal="0" CustomFormatter="{
  "$schema": "",
  "debugMode": true,
  "elmType": "div",
  "children": [
    {
      "elmType": "div",
      "style": {
        "display": "block",
        "width": "100%","color":"blue"
      },
      "forEach": "choice in @currentField",
      "txtContent": "[$choice]"
    }
  ]
}" Version="7">
                <CHOICES>
                    <CHOICE>Choice 1</CHOICE>
                    <CHOICE>Choice 2</CHOICE>
                    <CHOICE>Choice 3</CHOICE>
                </CHOICES>
            </Field>