Of course you can! This is an open source project!
Ideally, raise a tracker item in Sourceforge, so your patch doesn't get lost. Then chase up via the nagiosplug-devel mailing list, if nothing happens. But be aware, this project is run by volunteers, so there is not necessarily immediate response!
By submitting a patch, you are stating that:
If you disagree with handing over copyright, it maybe possible to dual copyright your change - please ask on the nagiosplug-devel mailing list.
We require the copyright ownership for legal reasons.
If your patch is accepted, we will: