Thanks for the tip! I'm looking at the D3400 almost exclusively and from the chart you provided (if I'm looking at it right) the lens I bought is compatible with no issues. Beginner's (read "Dumb") luck!
Geez, buying a DSLR is more like building a computer than anything else I've done
The problem is that Nikon compatibility is not as good as Canon.
Canon made a hard break back in the 80s when they changed mounts. And from what I understand, any EF lens can be used on any EF camera.
Nikon still uses the 1950s F mount, BUT it is all the other connections to the camera that have changed MANY times, and make the compatibility one of "it depends" on which lens and which camera.
When I look at a Nikon lens, I
have to look at that chart to see if it will work with my camera.