Nigeria claimed the first win of Sunday Oliseh's tenure on Tuesday as they saw off Niger in a 1-0 friendly victory at the Adokiye Amiesimaka Stadium.
Former Nigeria international Oliseh took charge as Super Eagles boss in July and saw his spell at the helm get off to a disappointing start with a goalless draw against Tanzania earlier this month.
However, CSKA Moscow man Musa struck from the spot before Simon wrapped up the friendly win in Port Harcourt with his first Nigeria goal.
Musa carried Nigeria's main threat early on, testing Daouda Kassaly with a shot from distance before Anthony Ujah caused the visitors' defence more serious problems, earning a penalty 10 minutes in.
That was duly dispatched by Musa, but Nigeria struggled to consolidate their advantage until seven minutes from time when substitute Simon put the game to bed.
Having replaced Musa shortly after the hour, Simon latched onto a sloppy clearance to beat Kassaly with a fierce drive from inside the area, opening his international account in the process.
Oliseh's men now turn their attentions to their African Nations Championship first-round play-off with Burkina Faso in October.
Get the best features, fun and footballing frolics straight to your inbox every week.
Thank you for signing up to Four Four Two. You will receive a verification email shortly.
There was a problem. Please refresh the page and try again.