Which sentence is written correctly?
a.
the large man would never hurt nobody.
b.
they haven't found anyone to with the decorations.
c.
sharon insists she didn't know nothing about her surprise party.
d.
lance hasn't started none of his homework so far

The correct sentence is B : They haven't found anyone to help with the decorations.

All of the other sentences have double negatives.
For instance, in A: never and nobody are both negatives. The correct sentence should be: The large man would never hurt anybody.

C: didn't and nothing. Sharon insists she didn't know anything about her surprise party.

D: hasn't and none. Lance hasn't started any of his homework so far.

B is written correctly.