There are several ways to answer that question.
Like - what year/model Tracker?
Like - whatever YOU can fit in it - I've seen an LS1 in a Tracker, so pretty much any 2.3 should go in with less difficulty.
Assuming you mean a 2.3 Suzuki enginr from an Aerio or similar ...
There are kits available to put a J20 2.0 engine into a first generation Tracker (<99), and it should not be too difficult to adapt that to fit a J23 2.3 engine, and if what you have is the second generation Tracker (99+), dropping a J23 engine should be an easy swap.
Easy, however, is relative - as far as I know the J23s were all transverse mounted so you're probably looking at fabricating all your own intake, exhaust & cooling system plumbing - which takes us back to my second answer - bolt-in swaps are rare, most require some fabrication, and your abilities dictate what's possible - either your ability to do it yourself, or your ability to pay someone to do it for you.