The Dagul Me'rvava (Y.D. 87:3) discusses the prohibition of meat and milk on non-kosher meat (neveila). He writes that the Rambam explicitly writes (ma'achalos asuros 9:4) that the issur to cook meat and milk of a ne'veila is d'oraysa, but the eating of it would not be a violation of eating meat and milk. The issue that the Rambam doesn't address in the halachos is whether there is an issur to benefit from the meat of neveila that is cooked with milk. The dagul m'rvava cites the rambam in his pirush hamishna in krisus (nekuda nif'la'ah) that it would not be an issur hana'ah and permits one to rely on this in a situation of loss of money - which would be the easiest heter for buying stock in McDonalds. The Chasam Sofer, cited by the Pischei Teshuva disagrees and paskens that there would be an issur hana'ah even by meat of ne'veila cooked with milk.
There seems to be a very strong proof from our gemara. The gemara says that the case of cooking a gid ha'nashe with milk and violating 5 issurim, is (at least initially) speaking about a gid ha'nashe (sciatic nerve) of a neveila. By establishing that the braisa is speaking about a gid of neveila that is cooked with milk, and one of the issurim that is violated is for eating meat and milk, clearly implies that there is an issur to eat meat of ne'veila cooked with milk. This would seem to contradict the Rambam who says that the issur of eating wouldn't apply, but perhaps the issur of eating would still be a violation of hana'ah. The gemara would therefore compel one of two things: either meat of neveila cooked with milk would be an issur basar b'chalav to eat in which case it is against the Rambam, or an issur to benefit which would be against the dagul m'rvava.