They put the pagans: prussians, pomeranians, pomeralians, etc in plantations. There is even one (wrong) economic theory that says the reason eastern germany is less developed economically than the west is because of the impact of those plantations. This model likley influenced hittler in some way.

As for nationalism. I think what differentiates nazis from other facists is that the former see the race as the mover of history while the later see the state. (Both are wrong, the correct answer is clases as defined by their relations to production, and race is not even a real thing) so this nazi may see the baltic conflict from a racial lens rather than a nationalist. Or more likley is thinking in anachronisms.

in that conflict the germans were the christians and the pagans were the balts and slavs... but this guy claims to be a pagan.