In NF3, nitrogen is having three bond pairs and a lone pair, hence, it has pyramidal shape.
The bond order of N2=3, and The bond order of O2=2. Bond length is inversely related to bond order. Hence, bond length of N2 is shorter than O2
Isoelectronic species have identical bond order

Dipole moment of H2O is more than that of H2S due to higher electronegativity of O.