The hybridization of N in different species is shown below. In NO2+, there are two bond pairs and no lone pairs. The hybridization is sp. Its geometry is linear as shown below.
In NO3−, there are three bond pairs and no lone pairs. The hybridization is sp2. Its geometry is trigonal planar as shown below.
In NH4+, there are four bond pairs and no lone pairs. The hybridization is sp3. Its geometry is tetrahedral as shown below.