actually good advice for staying under cover as a nationalist (or right wing in general) is just never bring up the stuff you "hate", talk about the things you love instead.

instead of talking about how much you hate immigrants for example talk about how much you love your history for example.

it's pretty good advice in general i see, it's easy to want to rant about all the fucking rot in the world, but if people don't understand what it is that is rotting, then you don't make sense, make them put thought into the things that matter in a country, then they will put 1 and 2 together.
this also protects you from the social nonsense game, never claim you "hate" something, just claim that you just really love "something" and if something threatens that thing you love, then say you are against it on that principle, use your words as to not alarm their double digit iq.