It’s possible by saving/loading tiles. I followed this: Navmesh "Chunks" - #4 by joshcamas
The part that’s not covered is removing tiles. There’s a list of tiles that you can get when loading in a chunk – just use that to clear tiles.
However, I ran into a separate issue. There’s an internal tile limit, and our game is multiplayer. A* Pathfinding internally stores tiles/nodes in a 2D grid, so chunks can’t exist in separate grid spaces without generating all tiles in between. So I can’t use this 
but maybe you can.
Going to use this later when I implement chunk loading internally.