when you see:
nvm is not compatible with the npm config "prefix" option
run this:
$ npm config delete prefix
$ npm config set prefix $NVM_DIR/versions/node/v6.11.1
when you see:
nvm is not compatible with the npm config "prefix" option
run this:
$ npm config delete prefix
$ npm config set prefix $NVM_DIR/versions/node/v6.11.1