ศาลาชุมนุม

What is the best colloquial Thai word to use to describe what we in the West would call nagging. As in to nag: to frequently criticize, complain, and find fault with another person on a frequent, repetitive basis.

Good one, Biff.

Here's some more along that line:

ถึงแม้แม่จะรู้สึกเป็นสุขแต่ก็ยังอดบ่นกระปอดกระแปดไม่ได้
Even though mother feels happy, she still cannot stop grumbling and complaining.

เพื่อนนักข่าวของฉันบ่นกระปอดกระแปดว่าหัวหน้าให้มาทำอะไรในพื้นที่แถวนี้หนอ ในเมื่อไม่ได้มีจุดมุ่งหมายที่ชัดเจนเลย
A reporter friend of mine bitches that his boss has him doing things in this location without any clear purpose.

On the other hand, I suspect that the OP is looking for a usage that not only includes incessant complaining, but has a husband, boyfriend, or related party as the object of the complaints, especially to do some task.

Here's another:

จ้องจับผิด = to watch intently for a mistake; look for 'gotchas'; find fault with

As in,

"ทั้งหูและตาของเถ้าแก่นั้น เหมือนจะคอยจ้องจับผิดเด็กลูกจ้างอยู่ตลอดเวลา"
The shopkeeper always kept his eyes and ears open for any little mistake his employees might make.

What about
เค้าชอบบ่น ... ปวดหัว ?
My Thai is rusty

I always hear when my thai friends girlfriend is complaining at him repetitively he replies sth like อ้าวอีกแล้ว