It is not possible to add node.js to a basic LAMP stack. All the components included in our stacks are built together to ensure they work properly. You can use the nodejs package installed in your system from the Bitnami LAMP Stack. Could you please give us more information about what are you trying to achieve?
Alternativelly, you can check our Node.js and MEAN stacks in case they fit your needs.
There is also another option: using the Bitnami Ruby Stack which, apart from Ruby and Apache, includes PHP, MySQL and Node.js
Hope it helps,