Answer
The compounds are diastereomers.
Work Step by Step
It can be seen that nothing changes for one chiral center while two groups on the other chiral center (the nitrogen) swap places. Whenever two groups swap places, the R/S configuration of the chiral center is flipped. So in the 2nd compound, one of the chiral centers has a different R/S configuration from the 1st compound. They are therefore diasteromers.
