I didn't realize it needed the insert.
Depends on the spindle on your lathe ...
Some people are working with your typical midi or mid range or full size lathe that have the 1 inch 10 teeth per inch spindle.
On the other hand, many of the mini lathes and some of the midi lathes use a 3/4 inch 16 teeth per inch spindle, in which case I would need that spindle adapter (the insert) in order to use the chuck, as I have a mini wood lathe.
I find that it fits pretty well inside the body of the chuck or other accessory, adding only 3/16ths of an inch to the front of my spindle. Very acceptable, and typically my chuck turns perfectly on center.
That's a decent price point for a Nova chuck, and it would use the C series of chuck jaws available from PSI as well! In my case, it made more sense for me (at the time, since it was on sale) to order PSI's general purpose C series chuck, with accessories. It was 89 dollars, plus 10 dollars shipping and handling ... came with the same insert, the chuck body, 3 sets of jaws, and as an added bonus it came with the jaw extensions with rubber gripping pins for turning a bowl or plate by the lip so that you can finish the bottom.
I think the main difference between my chuck and the nova is that the nova comes with a keyed chuck for one-handed operation, while I use the 2 tommy bars to tighten and thus it's more of a 2-handed thing. If that were more of a consideration for me, then yes ... I'ld shell out the extra 50 bucks to get the Nova. In any case, it's still a nice deal. As all the jaws I have for my chuck are 100% compatible with that Nova, I may decide to grab the main body of the Nova with insert for 104 dollars myself, and have a more convenient method for chucking up on the lathe while keeping a dedicated chuck for certain things that I do often.