Graduating a PMHNP program

Doesn't your program have this info?  It seems likely to vary state-to-state.  Admittedly, my memory is foggy because it was what all my peers were facing -- I already had a pedi NP, so all the hoops they faced were all set for me.

As I recall, you could take the exam pretty soon after.  If you look on the site for registering for the test, they tell you the requirements, and then you'd need to ask your school the timeline for them doing their bit of validating you graduated.  

After you test, then you get the state license - probably a few weeks.  (At least the test scores are instant these days.)

For DEA, you need to get your state NP license and also the controlled substance license, and then put them on the DEA application.  each one takes 2-6 weeks.  (And then they expire weirdly out of sync -- watch out, try to get the dates farther apart.  I had a DEA renewal get hung up because I had to get the state renewal to clear first.)

I'm pretty sure many jobs are used to hiring way before you're cleared to practice, since some things -- such as getting impaneled by insurance -- require you to have the supervising doc and practice address on the application.  I seem to recall my peers calculated that it would take 4-6 months before they could practice, with a good chunk of it needing to already have the doc and location set up.  Malpractice insurance is easiest -- once you do the form and give them a pile of money, it's almost instantaneous.

Me, I was weird.  Already had the NP license, had an office and supervising doc from my day job, and wasn't going to take insurance.  Since I already had the license, I could go ahead and get the DEA set up before I graduated, my boss gifted me the prescription pads (good old paper days), and the school had validated our eligibility to test as soon as grades were closed.  I figured if I really wanted to, I could take the test the afternoon after graduation and start prescribing that evening.  But like I said, I was weird.