I’ve been envious of the Sony bodies, but the thought of giving up my Nikon glass meant I wasn’t moving. I’ve been thinking about picking up a z6, but I’m not sure it’s worth the price.

From what I've seen, the D780 is a very well rounded 'best of both worlds' body. And I, having tasted the amazing quality and ease of use of video on the Z50, paired with forever-battery and very good focus system on the D750, am tempted to pick one up.

Is there no adapter?

There's always the dumb adapter that allows you to use without AF (and possibly lose aperture for some lenses) but I think there's like a 300 dollar one (nikon F to sony FE) that lets you use autofocus and whatnot.

But the general consensus is to get rid of your old glass if you're switching to mirrorless because the AF performance with adapters is on the "it barely works enough to not call it unusable" level.

This is a factor in me holding off from switching to mirrorless. Currently using the Nikon D50 which is dated now, and a handful of lenses which I am loath to give up on.

D50 is a great camera. I used one for years until moisture got inside while shooting pics of an incoming hurricane. I only by weather sealed bodies now :)

That's why I sold all if my AF Nikon F lenses and bought just two Panasonic lenses, the 40/2 and 14/2.8. The 14 will be replaced with a Leica 15/1.7 if I ever get serious about photography again. Until then I'm using an old Ricoh GRD 3, which is still amazing - no distorsion, great photo quality, great lens, stellar ergonomics.

Yes, there is. It comes for free (depending on source) with Nikon mirrorless cameras.

The F to Z mount adapter is ok from what I’ve read. The cross brand adapters usually have a lot of gotchas though.

I see videos from a lot of wildlife photographers who are using their big 600f4 lenses on Z6/Z7. It seems that adapter works really well.

Great to know since it’ll be awhile before they have lenses to replace my F mount ones.

Sure, you can get a $500 adapter to mount Nikon glass on a Sony body. There may be advantages (you already own the lenses, it throws a shitload of light onto a small area of the sensor) but there are also disadvantages (running at less than half of the resolution the camera body offers, fully manual operation). I personally wouldn't choose this route for a fancy body like the A9, but I think it's a reasonable choice when using a cheaper MFT body.