NERDCommenter works like this by default:
//level1
//level2
//level3
How do I get to work like this?
//level1
// level2
// level3
From the documentation:
[count]<leader>cl
[count]<leader>cb |NERDComAlignedComment|
Same as |NERDComComment| except that the delimiters are aligned down the left side (cl) or both sides (cb).