The problem
Even after installing the nomencl.sty , I am not getting nomenclature in my pdf document. The reson for this is that to print nomenclature, it requires use to run the following command in the Terminal.
makeindex paper.nlo -s nomencl.ist -o paper.nls

Once the .nls is build we can run pdflatex normally to get nomenclature. So the proper order of commands to run is:
pdflatex paper.texmakeindex paper.nlo -s nomencl.ist -o paper.nlspdflatex paper.tex
Note: All of the above commands are to be run inside the terminal. First navigate to the directory where you have you source latex file (paper.tex) and then run the above commands.