somebody asked about this the other day but i can't remember where. you cant automate the lfos of the nnxt sampler (to my knowledge), but there is a way to get around this - route the audio through a thor and use its filter/lfo. assuming you already have your sample in the nnxt, this is how its done:
1. create a thor
2. press tab to flip the rack
3. wire the left and right audio output from the nnxt into the audio input 1 and audio input 2 of the thor.
4. make sure the thor audio left and right outputs are going to the mixer
5. flip back round, turn off thors oscillators. set filter three to low pass filter.
6. in the grid of thor, set it out like this
source: audio1 in amount: 100 dest: Filt3 L.In
source: audio2 in amount: 100 dest: Filt3 R.In
source: LFO2 amount: 100 dest: Filt3 Freq
7. when u play a note using the nnxt u should be able to hear it being modulated by the thor filter.
8. now u can edit the automation for lfo2 rate/amount/whatever!
hope this helps someone