env: set NIX_BUILD_SHELL environment variable

.config/shell/env

@@ -9,6 +9,7 @@ if ! [ -d "$SHELL_CONFIG_DIR" ]; then
 fi
 
 if [ -z "$PROFILE_LOADED" ] && [ -f ~/.profile ]; then
+   # shellcheck source=/home/blake/.profile
    . ~/.profile
 fi
 
@@ -26,6 +27,9 @@ export VISUAL="$EDITOR"
 # Add local bin path and shell bin path to PATH
 export PATH="$PATH:${XDG_DATA_HOME:-$HOME/.local}/bin:$SHELL_CONFIG_DIR/bin"
 
+# Shell to use for commands like `nix-shell -p`
+export NIX_BUILD_SHELL=zsh
+
 # Basic default LS colors
 export LSCOLORS="Gxfxcxdxbxegedabagacad"