Can you trade your Pokemon into your Nintendo 3DS XL?

Yes, you can. The Nintendo 3DS XL is the same thing as the original 3DS except it has a 90% larger screen and better 3D and such. They are both compatible for the DS Pokemon games. I trade Pokemon all the time using both my 3DS and my DS Lite. I don't have a 3DS XL, but yes it will work on the XL since it is a DS system.