So I have a pile of dozens of used glowsticks in the corner of my room and I have no idea what to do with them and I can't bring myself to throw them out. Is there anything cool I can do with them/or the plastic covering alone/or the liquid alone?

in all seriousness, i don't think there's much you can do with those that's useful or constructive. Maybe break one over the mountain dew of one of your enemies. I heard they have pump your stomach when you drink that stuff.

research what's in them. That should give you a better idea. I know some things to do with used glowsticks. But I'm not sharing...

You can use it as a fluorescent dye.

If theres a little light left in them you can put them in hot water
or the microwave to get them glowing brightly again for a while.

Thats about it.

& what can you do with empty Nitros bottles?
They might make nice ends of the vertical metal rods on a wrought Iron like fence.