Yes you will be able to overclock the 1200 with that psu.
What will you be using this system for, I am guessing gaming?
Some improvements if your budget allows
-Adding an ssd, if you want fast load times
-Faster memory, works better with ryzen cpus
-Gtx 1060 6gb version, if you want to make your system future proof
-If you will not be upgrading to 16gb ram later on get 2x4gb ram rather than 1x8gb, this way the ram will be running in dual channel, which is faster than having one ram stick
This would be the ideal version for $900, if budget allows.https://pcpartpicker.com/list/8YxvLD