In detail, I wanted to machines of IC2 and Mekanism to generate HaC's heat, but there is no information for adding blocks with NBT tag to config files in the documentation.

No config documentation is available for support for NBT Tile. (There is no plan for that.)

It requires a modding technique, so it is not appropriate to support it in the config. I don't think I need to make up for the technical deficiencies of those who can't make add-ons.

If you do it as an add-on, you can do that by using BlockHeatTierEvent in the HaCAPI .
Here is an example plugin for a Simple Difficulty block.
https://github.com/defeatedcrow/HeatAndClimateMod/blob/1.12.2_v3/main/java/defeatedcrow/hac/plugin/sd/DCPluginSD.java#L108