2014 Nissan Maxima was driving, then all of a sudden can’t accelerate, lights flicker then eventually shuts off.

So as I was driving with my radio on and a/c going
with a full tank of gas when I push down on the
accelarator and get nothing. I drift to a service road
and try to rev the engine a few times while in park,
and it revs just fine. So I put it in drive and it still
wouldn’t accelerate. While all this is going on, I had
long since cut the ac and radio. The lights
eventually started flickering and went off. I try to
jump it with a portable jumper and everything starts
working like nothing happened, but the odd thing is
my portable battery didn’t lose any juice at all. But I
was able to get home taking local streets with no
issue. This is the second or third time this has
happened. I took the car to Nissan and they said
they couldn’t find anything wrong. Even the tow
truck operator when it happened before said the
battery and alternator seemed fine.