How much capacity do you need? It looks like that Chapin is 1-gallon. Only 1-gal power sprayer I know of are the Kobalt/Ryobi/Bauer ones that all seem to be the same basic device but sold from the respective stores for the respective battery-pack systems. However, I can't really tell if the wand will take a TeeJet nozzle or if that brass head is built-in like your Chapin.

Most of the sprayers from The Fountainhead Group (DB Smith/Field King/half a dozen private brands) do work with TeeJet and come with their own assortment of similar tips. They have a couple of non-backpack 2-gallon tanks sold with battery pumps. Heck, they even sell the pump unit separately.

If you don't already have a cordless tool ecosystem to buy into, this one might be your best bet and what /u/crozbot87 is referencing.

I have the manual version (rebadged as Husqvarna) and it's worlds nicer than the cheap $15 tanks. Metal pump rod and a pretty consistent spray, and I get a lot of coverage between pumps. Maybe pick up one of those in the interim, and later on buy the electric pump head? just a thought.

Not to nerd out about spray cans, but I'm just a tool nerd in general.