If your icons are used for UI only, and are scale appropriately, then yes I’d think it would be okay to disable your mipmaps for those textures.
Instead of manually setting the MipMap settings, look into setting the TextureGroup to UI on your texture. That will disable mipmaps for that texture, as well as set some other settings that are helpful for UI textures.
If you select all of your icon textures in the content browser, you can use the bulk edit option to set the Texture group on all the textures at once.