first create a configuration file, say config.json, that looks like follows:

{
  "nick": "somenick",
  "useNickServ": false
}

or, if the nick is registered with NickServ, then:

{
  "nick": "somenick",
  "pass": "somepass"
}

then enter the Nix shell for development:

cabal2nix . > default.nix && nix-shell -I stockholm=~/stockholm

and run the REPL:

build
run config.json

or, interactively:

ghci -isrc -Wall src/main.hs
withArgs ["config.json"] main
:r