Thanks. I was aware of Nb5 but never really thought about Nxd5 except for one time when I did take the second pawn and it became an issue.. My main goals at these points has been to play Ng8-e7 and sometimes from there to c6 and to get the queen to a safer location. After that it's not a big deal to reorganize and use that extra pawn to good affect.
I will have to look at that line from Keres.
10. Nc3 develops quickly a piece (one of the main aims of this gambit) and also aims at:
a) Nb5 (attacking the Queen)-Nc7+ or similar, or
b) Nxd5 if the e6-pawn is pinned (i.e. after 10. ... Qxe5 11. Re1).
The Knight clearly belongs to c3, while the Queen may be better at f3 (supporting Bf4), or g4 (attacking g7), etc. in some variations. Moreover, White actually prefers (at least I!) to lure the Black Queen to take the 2nd pawn as he gains good attacking possibilities despite the pawn deficit.
Now, 10. Nc3 a6 11. Qe2 has similarities to 10. Qe2 in that it may result in a more positional game. White will play positionally (despite being a pawn down!), his pros being:
a) his greater space,
b) slightly better development (the Black Q will be harassed again), and
c) the use of d4 as a useful pivot point for his minor pieces.
The e5-pawn needs to be carefully defended (e.g. f4 may be needed) and gradually there could be prospects for a K-side attack..
Now, in case you are familiar with the strategic points I've made above and you only need some concrete lines, the most I could find is:
10. ... f6!? (suggested by Keres) 11. exf6 Nxf6 12. Rd1 Qh4; or 12. Nc3 Bd6!? 13. Nb5 Qe5 (Watson)
This looks quite different than the usual 10. Qe2 a6 11. Nc3 or 10. Qe2 Ne7 continuations, but I have not seriously analysed it to see if it works out well (and if it is the refutation?!?!?!

)
Hope this helps..