This was on the Nosler website:

Case Capacity

The 22 Nosler case holds 34.2gr H2O at overflow, and 31.2gr H2O with a 55gr Ballistic Tip® seated to 2.260” OAL. For comparison, a 223 Remington case holds 27.4gr H2O with a 55gr BT seated at 2.260” OAL. The 22 Nosler has almost 25% more case capacity than the 223 Remington.

This I in a review of the 22 Nosler that provides the same info and a little more..

"How does Nosler's case volume compare with the .223 Rem.? Well, the .22 Nosler case holds 34.2 grains of water at overflow while a .223 Rem. case holds approximately 31 grains. With a 55-grain Ballistic Tip seated to a provide an overall length of 2.260 inches, the .22 Nosler holds 31.2 grains of water. A .223 Rem. with the same bullet seated to the same overall length holds 27.4 grains of water. So Nosler's new case does offer a useful increase in case volume."

"The .22 Nosler is a good-looking cartridge, a bit fatter than the traditional .223 Rem. but similar in length. The bottleneck case sports a 30-degree shoulder and a distinctive rebated rim. Putting my calipers to some virgin cases showed the case to have an overall length of 1.75 inches, tapering from 0.415 inch to 0.395 inch. It has a neck diameter of 0.252 inch, and as mentioned above, the rim is rebated to fit a standard 0.378-inch .223 Rem. bolt. It utilizes a Small Rifle primer."

"Nosler's engineering team also had to consider the pressures this design could safely handle. The SAAMI maximum average pressure for the .223 Rem. is 55,000 psi, and that's what the pressure standard for the .22 Nosler is as well."