Words that end with 'nning'

We've come across a few words that end with 'nning' recently, and found that many of us are not sure when it should be 'ning' and when it should be 'nning'. We're going to find lots of 'nning' words first, and then we're going to see if there are any rules for speeling words with 'nning' and not 'ning'.

Here's some to start with, add more in the comments.

Running
Planning
Winning