"Good" works but "nice" doesn't in that context.
"A good five steps" means that you're sure it was at least five steps and it could even have been a little bit more.
- I'd like to walk to the library. How far is it from here?
- It's a good four miles. I think it's too far to walk. I suggest you get the number 17 bus from just across the road.
Student or Learner