If I specify a particular venue, does Reg NMS still require my order to only be filled if it's within the national best bid-offer (NBBO) range? If not, that would seem to be a big caveat that should be mentioned whenever mentioning that retail inventors can specify a specific venue.
(Disclosure: I work on the sell-side, but don't have a Series 7. Certainly, for vanilla orders, Reg NMS requires your broker to route your order for best price. If you're specifying the routing, though, I'll leave it to someone with a Series 7 to explain which Reg NMS protections still apply.)
The short answer is "yes" but there's a lot of nuance to it. Reg NMS does not require routing of anything - a very common misunderstanding. Reg NMS does not get you the "best price", it prevents the execution of trades at prices inferior to protected quotations displayed by other exchanges.
(Disclosure: I work on the sell-side, but don't have a Series 7. Certainly, for vanilla orders, Reg NMS requires your broker to route your order for best price. If you're specifying the routing, though, I'll leave it to someone with a Series 7 to explain which Reg NMS protections still apply.)