Titan's atmosphere is mostly nitrogen , but also methane , ethane and possably amonia, at -180C ( -356F ) basicly all of that is liquid , concidering that the air we breathe is about 80% nitrogen , and methane is one of the basic building blocks of life , toss in massive plate tontonic movements due to saturns gravity ( i.e , underground heat ) toss in some sulfur and phosphorus ( plate tectonics make this probable ) and hydrogen ( not like thats hard to fin in the universe ) and the possability of life or at least basic protiens is highlty possable.
carbon is the wild card , it's needed for any sort of life and it's not found all that often. But you also have to concider that this solor system ( and most likely a few dozen around us ) all came from the same nova "cloud" and in all probably all have basicly the same elements , us , venus , and mars just sit right where the heaver eleiments would of drifted in twords the sun and not be blown away when it ignighted , hance the gass giants farther out , the the moons of the gass giants are pieces of "other stuff" thats been floating around the area ( ok , a very large area ) and got caught in orbit then formed the moons ... at least thats what all the current theories say.
So finding all the same elements in all the local planets/moons wouldnt suprise me much , even in the next few systems over.
oh ya , it' common for biologests to dump all the basic elements in a sealed jar , add electricty , heat and time , and sooner or later , the basic parts of protiens will form , of course no one has left a jar like that for 4billion years , so we really dont know if anything would come of those protine parts.