First, we need to find the total number of books in the school library by adding the number of fiction books and nonfiction books together:
1,876 (fiction) + 2,954 (nonfiction) = 4,830 books in the school library.
Next, we compare this total to the number of books in the town library, which has 4,210 books.
Now, we find how many more books are in the school library than in the town library:
4,830 (school library) - 4,210 (town library) = 620.
So, the answer is 620.