I find that the isolation of Nix/Nixpkgs makes it pretty natural to use it in tandem with Homebrew.
I don't need any CLI tools that aren't in Nixpkgs anymore, so I use Homebrew exclusively as an installer-fetcher-and-runner rather than a source-based package manager (i.e., only for ‘casks’ rather than for ‘formulae’), and the combination is very nice.
Nix similarly plays nice with Pkgsrc and MacPorts, so if you're interested in switching away from Homebrew but unsure about Nix, there's no special work you have to do to install one of those alongside Nix for use as an escape hatch that doesn't involve Homebrew.
I don't need any CLI tools that aren't in Nixpkgs anymore, so I use Homebrew exclusively as an installer-fetcher-and-runner rather than a source-based package manager (i.e., only for ‘casks’ rather than for ‘formulae’), and the combination is very nice.
Nix similarly plays nice with Pkgsrc and MacPorts, so if you're interested in switching away from Homebrew but unsure about Nix, there's no special work you have to do to install one of those alongside Nix for use as an escape hatch that doesn't involve Homebrew.