He had acknowledged earlier in his administration that DACA was outside his authority.

Here is the YouTube of his explanation of why DACA would be illegal.   

Twice.  

Then they show his "I can do anything I want because I'm President" statement.

Trump is now President so he 'can do anything he wants'!

What goes around comes around!

https://www.youtube.com/watch?v=Gw4BIWiWyQg