My favorite books to have my parents read me were the Chronicles of Narnia series by C.S. Lewis. However, while those books were great for kids five years old and older, they may be a little bit too old for your nephew. In that case, I would recomend the Berenstein Bear series, I always found them funny when I was little.
I took Berenstein Bears out of my house years ago. Papa Berenstein was always made to be a stupid boob. No way I wanted them in my house, around my kids. It so happened that my ex was a very difficult man who was distant from the kids and everyone else.
but I didn’t want to reinforce his lacks and I found it disrespectful to men and fathers.