CWO_Mustang
From past experience I don't think they are the same.
In the US Navy a Chief Warrant is a Commissioned Officer and is intended to serve in a technical field. They have all the status and privileges of an Officer. In the US Navy all Chief Warrants were Chief Petty Officers (or Senior or Master Chiefs) prior to appointment. (USMC has different requirements)
Depending on the command (and the Commanding Officer) a USN CWO can be the Skippers "special councilorâ€, another officer, or a CPO that they must allow in the Ward Room.
In linier ranking a USN CWO is between an Ensign and a Master Chief Petty Officer. In practice a USN CWO will (usually) fill a billet equivalent to a Lieutenant or a Lieutenant Commander.
Several years ago USN had CWO Nurses, these were Nursing School, Community College (2 yr) Nurses. Upon completion of their 4 year degree the nurse became a Lieutenant Junior Grade.. (program now discontinued) .. upon hearing of the program an officer remarked “now they have Nurses that can yell at youâ€..