how to use nbdime diffing and merging for jupyter notebooks in git bash

I can not use the diffing and merging for jupyter notebooks provided by nbdime, when I am using git bash. However, It works, when I use a cmd console.

I have installed git (including git bash) from the git-scm-website.

I have installed nbdime in anaconda using pip, as described on the nbdime-website.
I have also followed all the instructions for integrating the nbdime functionalities into git, as decribed on the corresponding page. Namely:

nbdime config-git --enable --global

And I have also modified my global .gitconfig-File, to use graphical diffs as standard. Now it looks like this:

    clean = git-lfs clean -- %f
    smudge = git-lfs smudge -- %f
    process = git-lfs filter-process
    required = true
[user]
    name = UserName
    email = UserEmail
[diff "jupyternotebook"]
    command = git-nbdiffdriver webdiff
[merge "jupyternotebook"]
    driver = git-nbmergedriver merge %O %A %B %L %P
    name = jupyter notebook merge driver
[difftool "nbdime"]
    cmd = git-nbdifftool diff \"$LOCAL\" \"$REMOTE\" \"$BASE\"
[difftool]
    prompt = false
[mergetool "nbdime"]
    cmd = git-nbmergetool merge \"$BASE\" \"$LOCAL\" \"$REMOTE\" \"$MERGED\"
[mergetool]
    prompt = false

As mentioned before, it works in a cmd-console. But I do not want to have to switch all the time between bash an cmd when I want to diff or merge jupyter notebooks.

When I use a diff command in bash, I get something like this:

Or when I use a merge command in bash, I get something like this:

It always says "command not found". Any ideas how to solve this?
Maybe it is something with the installation of nbdime (using anaconda)?