Not too much. If you secure nano, you can recycle the robo and sentries in base for res to cap nanogrid, then leave two marines in nanogrid to cap. The other two either go lane, respawn or type kill in console to force respawn. You have a lot of options then.
you could get an armory at nano and research landmines, then the guy can solo defend nano with the sentries and mines. The rest of the marines are free to pressure/lane. Veil does not have as forgiving expansion lanes as something like northside jambi or tram. It's very easier to pressure places like cargo , pipeline and sub, and dedicating a marine to secure two nodes and deny nano to aliens is a good trade.
Bottem line is that you need to crush their push into nano, or get at least three picks since they won't be able to reinforce since 3 marines need to spawn on 1 ip.