I dont think it does yet ( if it does, i have never found it, but to be honest, i have not gone looking before today), you just edit it through the "MapTilesets.yml" file in your favourite Text Editor, you will find this in the Settings folder of Mapview2.
the Process is:
Manually duplicate your desired .map file and .Rmp files, renames these to what ever you want
Open MapTilesets.ym
Edit the file to create your new map names
as you can see below, the format of the MapTilesets.ym is pretty straight forward:
#----- base XCOM --------------------------------------------------------------#
- type: XBASE_00
terrains:
- XBASE1
- XBASE2
category: base XCOM
group: ufoLandscapes
- type: XBASE_01
terrains:
- XBASE1
- XBASE2
category: base XCOM
group: ufoLandscapes
- type: XBASE_02
terrains:
- XBASE1
- XBASE2
category: base XCOM
group: ufoLandscapes