Any minor effect of lift geenrated directly by the engine nacelles is unfortunately countered by the serious disturbance to the wing flow created by the nacelles and pylons. Engines mounted on the wing are generally a net decrement to the lifting capability of the aircraft (with the obvious exceptions of powered lift, both hjet and prop).
Furthermore, the main effort behind any nacelle shaping will be to provide the best possible conditions for engine operation; no other requirement is as important. It's simply not worth compromising on that one to generate a little bit of lift.
As an aside, a body doesn't have to be "aerofoil-shaped" to generate lift, of course. Underwing stores (e.g. fuel tanks) are longitudinally destabilising when projected forward of the leading edge because they generate lift. And aft-mounted engines act to stabilise the aircraft slightly, in the fashion of a very inefficient tailplane. But neither case is designed to do that.