Is this suitable for Nitecore P20i UV compact 1800 lumen USB-C rechargeable LED torch

Sadly no. The Nitecore P20i UV (and other I series Nitecore lights) come with a 21700i series battery like the Nitecore NL2150HPi 5000mAh 21700 15A rechargeable Li-ion battery.

These I series batteries have positive and negative terminals at both ends, unlike most a batteries which have one at each end.  

 Many of the Nitecore I Series lights also include a CR123 battery magazine which allows the light to also use two displosable CR123A batteries.