I just completed this swap this summer. It nice extra power, lots of fun to drive. But it does come with some interesting problems.
For the swap and some finished fitment photos, see my thread in the build diary section, 1.6 to 2.3 in 95 Sidekick.
The auto causes the biggest issues. I used the auto from my 2000 tracker donor. The switches for the power mode and overdrive are missing in the 95 shifter, the 2000 assembly didn't fit in. So opted to keep the power mode on permanently, recommend this, and added a micro switch for the AOD. The setup works great and its fun having power mode engaged all the time, adds to the peppy, fly by the seat, fun to drive feel. I am still running stock gears, tires and suspension so its really noticeable. Will eventually switch to 5.12 gears and 32" tires, looking for a rally type setup.
You will need a donor 1.8l or 2.0l engine for oil pan and other rear drive accessories. Mine is a 2.3l block and head, used rest of parts, intake, exhaust, fuel rail, injectors, harness and computer from 2000 tracker donor. It's easier then getting the 2.3l computer to mate to and accept the auto tranny. I didn't dyno it but the butt feel while driving tells me it's peppier than my 2002 2dr Tracker. You will also need the dash harness, which was modified by Trail Tough to make it work best.
Now since doing it one way, and thinking i may do it again in a tin top, I have a few different ideas to do it.
Now since you have a newer version than I, it may be a little different, smarter folks than I can chime in.
To me, having only looked and not done the measurements to confirm yet. I would get a donor 96 - 98 sidekick sport with a 1.8l and manual, but auto may work. Since the interior and dash to the 96 - 98 sidekick and sidekick sport looks the same, and under hood dimension are similar (to be confirmed). I was thinking swap engine, harness, dash, harness and tranny from the sport to non sport model, this gives you a fully functional 1.8l and complete harnesses in place of the 1.6l. Once this is in and running, swap out the 1.8l for the 2.3l like the article for the swap in the sport model. This seems like an easier route than my first swap. Again this is just my plan in my head at this time and haven't finished the research into the swaps, other than learning from my errors and problems from my swap.