Lecithin is usually from soy.  However, it has no protein (per USDA) so it
may not be a problem.

If you want chocolate chips free of lecithin (and dairy), look for one of
the kosher-for-Passover brands.

Another way is to make your own.  Unsweetened chocolate does not contain
lecithin--or you could even use cocoa.  (I don't know if semi-sweet baking
chocolate is lecithin-free, but if it is, it should work.)  the hardest
part is getting the cocoa butter--I do everything else in the
microwave--and the freezer so I can eat it right away (it just takes a few
minutes).

Melt it with cocoa butter (from a candy-making supply place or off the
Web), add sweetener of choice, vanilla or other flavor, and some coconut
milk if you want a fudgy texture.  If you use enough cocoa butter, it even
comes out a bit like milk chocolate.  Add nuts, seeds, raisens, coconut, or
whatever (optional).   Cool.

Barbara