Simplification of the boolean expression
You still messed up your initial statement.

((A NAND B) XOR (B OR C)) AND C

((AB)'(B+C)' + ((AB)')'(B+C))C


Note it's an AND between the ((AB)')' and the (B+C).

I hope you can get it from there. Still highly suggest making a truth table. It's super obvious what the answer is if you draw out the truth table.