How do I enhance my male sim? Like bigger muscles, more sculpted body and such. Is there a advance tab I am missing?

There are three sliders that affect a male sim's body. Weight, muscles and muscle definition. Now if you put your weight into the least possible and muscles as big s possible it's not much, try increasing weight, playing around with the definition. However, the end result is fairly realistic while not most common in any extreme setting. If you want your sim to look like Marvel characters you'll need mods. Search with the keyword "Bodybuilder", that is the name of a series of bodysculpting options by one modder.

Cool, one more is it a mod I need if I want to add nips to my male Sims?

to add nips, you need a custom skin. there are literally hundreds to choose from, and some actually have more defined muscles drawn into them, so you would just need to find the one you like and install it. Some are Default Skins, meaning they over ride the EA skin, and some are non-default, meaning you have to apply the skin in CAS. There are skins on this site and many more. You could look through the downloadable sims on this site, as many use custom skins and will contain links to them.

Along with these tops by alex_stanton1983 and the fitness override by Consort. Other than that, downloads for male sims in the Sims 3 are pretty scarce. You could probably find better luck with female sims.

http://www.thesimsresource.com/arti.../page/2/cnt/41/
http://modthesims.info/download.php?t=470349