"You cannot perform the requested operation.", code: "AccessDenied", method: "addTable", line: 9}

BradynHin 

Can't reproduce such error, even on protected sheet. If you run on new workbook with such named sheet, do you have an error?

Just in case, slightly modified the script

function main(workbook: ExcelScript.Workbook) {

try {
  const stuChassis = workbook
    .getWorksheet("STU Chassis")

  const stuChassisUsed = stuChassis
    .getUsedRange()

  stuChassis
    .addTable(stuChassisUsed, true)
    .setName("STUChassisTable")

}

  catch (error) {
    console.log("There are already tables present in STU chassis");
    console.log(error);
  }

  return

}