I am thinking to put some 5/16" hardwood floor on my stairs.
I have to cut off the nose from the 1" ply treads in order
to put the hardwood nose on it.



Every power tool I can think of will stop cutting when the body of the runs
into the side of the stairs. A good circular saw is a good choice; forget the
recip saw.

You could rough cut it with the cheap circular saw & then finish up with a
flush cutting router bit that has bearing to guide against the lower riser.

You still have to contend with the "un-cut" section at each end of the tread.

Sharp chisel & patience could do the end work. How many treads? 12?

since you're covering the treads with flooring, could you pull out the treads &
rip the nose off on a table saw & re-install?

Bob