How to install and then update the LTS version of Node.js and the current one through nvm?

Question

Node.js

I installed the current node version 15.3.0 using the distribution, then installed nvm in the same way, since I have Windows. I would like the computer to have the last two versions at the same time - the current one and LTS, while being able to update them independently. I installed the LTS version with the command nvm install 14.15.1, and now nvm lsboth versions are shown after.

And how now independently to update these versions?