Take the plastic cap off of the chain lube can and lay it on a flat surface with the top down. Now poke, punch, or drill a small hole off center slightly smaller then the plastic applicator tube diameter. The applicator tube should fit snugly in the cap so take your time and trial fit the applicator tube in the cap to make sure it fits in the cap hole but won't fall out when the can is turned over
The reason for putting the small hole off center in the cap is that once you re-install the cap and slide the applicator tube in the cap for storage the applicator tube must clear the lube release valve which sits high inside the center of the cap.
You may want to cut the tube in half for more accuracy while applying the chain lube plus you can put the other half of the tube in your tool box just in case you still lose the original.
There you go, a simple solution to a old problem.
R.E.A.R.