Making a plastic nut is easy. To make it, you need a plastic bottle, a knife or scissors, a bolt, a soldering iron.
First you need to cut the bottle and cut a plastic strip. The width of the strip is approximately equal to the width of your nut, but it is better to take a little more, you can always cut off the excess.
Next, you need to wrap a strip around the bolt twice. Solder the edges of the strip with a soldering iron.
Now you need to solder the plastic along the entire length and circumference with a soldering iron. This will be the base of the nut. The plastic from heating should compress the threads on the bolt.
Then as many layers of plastic tape are wound as you need the outer diameter of the nut. Instead of a soldering iron, you can use a hairdryer, a heated nail, a torch. After winding the tape, the nut is twisted from the bolt, cut if necessary.
Here's a way to make a nut.