Wiberg bond indices calculation provides bond order which maybe proportional to the bond strength. But Bond strength calculation is possible without doing wiberg calculation. For example if you want to know the strength of A-B bond. Then calculate the energy of AB, A & B (separately). E(A) + E(B) - E(AB) will be the bond strength. You should be careful about the bond dissociation mechanism either it is hetero or homolytic and also basis set superposition error.

Wiberg bond indices calculation provides bond order which maybe proportional to the bond strength. But Bond strength calculation is possible without doing wiberg calculation. For example if you want to know the strength of A-B bond. Then calculate the energy of AB, A & B (separately). E(A) + E(B) - E(AB) will be the bond strength. You should be careful about the bond dissociation mechanism either it is hetero or homolytic and also basis set superposition error.

Actually, if A is making bond with B and C (both), then i want to compare them and find with which atom A is making strong bond.

You simply have to do two bond strength calculation. In that case bond order calculation maybe easy. In one calculation you get the answer. There are many other ways to compare bond strength other than Wiberg calculation if is not available in NwChem. You can look for Atoms in Molecules analysis or Multiwfn package.

Thank You @Debashish Mandal. I will try Multiwfn package for the calculation.