godan verb (-ru), intransitive verb
be perfectly content with one's position; be smugly satisfied
Often carries a nuance of self-satisfaction or smugness, implying the person is settled into a comfortable position and feels no need to change or improve.
彼は今の地位に納まり返っている。
He is perfectly content with his current position.
あの政治家は批判されても
That politician remains smugly satisfied even when criticized.