#include <StringConstants.au3> ; to declare the Constants of StringRegExp
#include <Array.au3> ; UDF needed for _ArrayDisplay and _ArrayConcatenate
Local $sRegex = "(?mi)\b(([A-Z])\w*(?:\s+\w+)*?)\s*\((\2[A-Z]*)\)"
Local $sString = "Some example text (SET) that demonstrates what I'm looking for. Energy system models (ESM) are used to find specific optima (SCO). Some say computer systems (CUST) are cool. In the summer playing outside (OUTS) should be preferred. Stupid example(s) Stupid example(S) Not stupid example (NSEMPLE), bad example (Bexle)"
Local $aArray = StringRegExp($sString, $sRegex, $STR_REGEXPARRAYGLOBALFULLMATCH)
Local $aFullArray[0]
For $i = 0 To UBound($aArray) -1
_ArrayConcatenate($aFullArray, $aArray[$i])
Next
$aArray = $aFullArray
; Present the entire match result
_ArrayDisplay($aArray, "Result")
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for AutoIt, please visit: https://www.autoitscript.com/autoit3/docs/functions/StringRegExp.htm