Last fall, I purchased a set of four TPMS sensors for $15.88 each on eBay, for some alloy summer wheels (TireRack wanted $42 per TPMS sensor). I swapped winter/summer wheels yesterday, and the TMPS alarm came-on after about 10 minutes of driving, as expected. Today, I used the TMPS Registration function of LeafSpyPro, and it worked fine: the four sensors registered, and the new pressures are showing in LeafSpy.
FYI, my leaf is a 2017 model S. If I recall, I looked at the OEM sensors from inside my wheels, copied down the ID numbers, and then searched eBay for similar ID numbers.
The sensors I bought were from eBay seller "connectedauto" in Farmington Arkansas, with a sale title "Nissan-TIRE-PRESSURE-SENSOR-TPMS-TPM-Factory-OEM-Pacific-40700-1LA0D-TS-NS23". (PM me if that's not enough info to find the auction).
Cost was $15.88 per sensor, including shipping. Condition of the sensors was listed as "Used". Since they are used, maybe the TPMS battery will run-out tomorrow; or maybe it will run for 8 years instead of 10 years. I took a chance, and it looks like they work fine.