you almost surely have a loose image, calling with K6, being young etc...
surely not nitty.
against a guy i just stacked and maybe has got revenge on his mind, i probably just play it straightforward and CALL. he gives us huge odds, and if we hit our Q or A, he might not believe us anyway. if we raise he might shove his 45 or Tx which is a horrible result for us.
call and surprise him with his overs
i´m not saying a raise is bad per se, but it might get awkward to play since please dont expect him to fold a better hand. you should be capable of good turn and river play if you decide to raise.
another point which leads me towards calling is we keep in their QJ, AJ, KQ etc and might even "cooler" someone on the right turn.