In NO3−,H=21[5+0−0+1]=3 Thus, in NO3−, the central atom is sp2 hybridised and it has trigonal planar geometry. 
In H3O+, H=21[6+3−1+0]=4 Thus, O is sp 3 hybridised in H3O+and H3O+ has pyramidal geometry due to the presence of one lone pair of electrons.