How many sigma bonds does NBr3 have?

It has 3 sigma bonds

Explanation:

A sigma bond is a covalent interaction between two atoms, these bonds are the strongest type of covalent bonds and they are formed by the overlap of atomic orbitals.

The nitrogen is bond to the bromine atoms through sigma bonds, which means that exist 3 sigma bonds in the molecule.

this molecule has a trigonal pyramid geometry due to the free pair of nitrogen electrons.