Hee Hee Hee...
Boss Nass is the creepy boss of the Gungans who lives on Naboo.
He doesn't really do anything of any note, apart from lead the Gungan army to failure. He would have died along with his army had pure fluke not meant that the entire CIS forces were one-shotted because their control ship was destroyed.
He is a big, fat Gungan who salivates all over the place. That's all you need to know.
Boss Nass is the Bomb
Boss Nass like a Boss