JSON Formatting to Show button in SharePoint List based on multiple values from same column - can't get it to work

I am new to JSON and have created a button to show in a sharepoint online list based on Agenda Item (choice column) equals Assistance Request. I've been asked to have the button show if a user selects Assistance Request or Call to Action.

I've tried this JSON but it doesn't show the button when Call to Action is selected. 

Any help is greatly appreciated.

{

  "elmType": "button",<o:p></o:p>

  "txtContent": "Create Task",<o:p></o:p>

  "customRowAction": {<o:p></o:p>

    "action": "executeFlow",<o:p></o:p>

    "actionParams": "{\"id\":\"23573da5-6b59-4937-8fdc-20743384db25\"}"<o:p></o:p>

  },<o:p></o:p>

  "style": {<o:p></o:p>

    "background-color": "grey",<o:p></o:p>

    "color": "white",<o:p></o:p>

    "visibility": "=if([$Item_x0020_Category]== 'Assistance Request','visible','hidden',if([$Item_x0020_Category]=='Call to Action', 'visible', 'hidden')"

  }

}