• Operating system and version:

Linux i3 4.4.0-66-generic #87-Ubuntu SMP Fri Mar 3 15:29:05 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux

• nvm debug output:

nvm --version: v0.32.0
$SHELL: /bin/bash
$HOME: /home/mrm
$NVM_DIR: '$HOME/.nvm'
$PREFIX: ''
$NPM_CONFIG_PREFIX: ''
nvm current: v7.7.1
which node: $NVM_DIR/versions/node/v7.7.1/bin/node
which iojs:
which npm: $NVM_DIR/versions/node/v7.7.1/bin/npm
npm config get prefix: $NVM_DIR/versions/node/v7.7.1
npm root -g: $NVM_DIR/versions/node/v7.7.1/lib/node_modules

• nvm ls output:

$ nvm ls
        v5.12.0
         v6.2.2
         v6.5.0
         v6.8.0
         v7.6.0
->       v7.7.1
default -> node (-> v7.7.1)
node -> stable (-> v7.7.1) (default)
stable -> 7.7 (-> v7.7.1) (default)
iojs -> N/A (default)
lts/* -> lts/argon (-> N/A)
lts/argon -> v4.8.0 (-> N/A)
lts/boron -> v6.10.0 (-> N/A)

• How did you install nvm?
  install script in readme

• What steps did you perform?
  Building native npm dependencies

• What happened?

gyp WARN download NVM_NODEJS_ORG_MIRROR is deprecated and will be removed in node-gyp v4, please use NODEJS_ORG_MIRROR

• What did you expect to happen?
  No warnings

• Is there anything in any of your profile files (.bashrc, .bash_profile, .zshrc, etc) that modifies the PATH?
  Yes, but that's irrelevant here.

¿por qué no los dos?

I don't know how many other systems look at these variables, so the safest (and most-chicken^H^H^H^H^H^Hconservative) solution would be to set both MIRROR values with and without the NPM prefix. The following, added to my ~/.bashrc after the call to source nvm.sh, removes the node-gyp warning:

export NODEJS_ORG_MIRROR=${NODEJS_ORG_MIRROR-$NVM_NODEJS_ORG_MIRROR}
export IOJS_ORG_MIRROR=${IOJS_ORG_MIRROR-$NVM_IOJS_ORG_MIRROR}

FWIW, I didn't have to unset NVM_NODEJS_ORG_MIRROR. Having both set seems harmless.