I think it would be Psy-kun no Ochinchin rather than Ochinchin no Psy-kun.
The example I use to remember this shit from the textbook was this
The Hotel's Pool
and
The Pool of the Hotel
Both of these are said as 'Hoteru no Puuru' ホテルのプール
The pool belongs to the hotel, possessive I think is the phrase and so the possessor goes before the object in nipponski sentence structures.