Safest is aftermarket engine management like zaidallas said. While I'd rather run anti-lag and an intercooler than use nitrous to spool the turbo and cool my engine I do know the Haltech can do a lot with this. If you install an EBC and run base maps at 5psi then tune peak boost maps for 8-9psi + fine tuning for the nitrous input and activate the EBC and the nitrous system simultaneously (which the Haltech can help out with) you could be pretty safe. Or you can just use the nitrous to spool the turbo instead of buying a ceramic impact bearing turbo like I did for anti-lag
Intake temps don't suffer too terribly when you've got an intercooler. I've been watching intake temps off my intercooler lately and they keep pretty low, even with the TMIC. And with proper engine management you wouldn't really need the extra cooling of nitrous, especially since you aren't constantly running with it on.