Munchlax doesn't evolve based on level; when its happiness is at maximum, it will evolve the next time it levels up.
Munchlax evolves by happiness. As long as it has a high happiness and it levels up, then it will evolve.
go to serbii.net or munchlax serbii.net
level 40
Level 32.
Level 30.
level 26 ^^
On level 20.
Level 16
Level 16.
at level 32
At level 59
it will evovle at level forty-five