From a regulatory standpoint, all RNAV(GPS) approaches are nonprecision. But the only practical effect of that designation is that if you're using an RNAV(GPS) approach as the approach for designating an airport as your filed alternate, it must be forecasting at least 800-2 even if it has an LPV option. You still fly an LPV using precision technique, that is, you follow the glide slope down to the published DA and then begin executing your missed approach when you reach DA regardless of relationship to the missed approach waypoint (RWxx waypoint) which you'd use if you were flying it in LP or LNAV mode. And, of course, just as with any other approach, if you divert to an alternate (filed or not) after missing at your destination, you can fly the approach down to the MDA/DA minimums published for that approach, not just the "600/800-2 or as published" alternate weather requirement. Also, you can use an LPV as your precision approach on an instrument practical test or instrument proficiency check (IPC) if the DH is 300 or less. But even so, it's still legally a nonprecision approach.
LPV approaches are a WAAS/GPS based approach, and they're very similar to the ILS. But there is a difference. Even though LPV approaches have vertical guidance, they're not considered precision approaches. Instead, they're an approach with vertical guidance (APV).
So what's the difference? APV approaches don't meet the ICAO and FAA precision approach definitions, which apply mostly to localizer and glideslope transmitters. The precision approach definition also carries a lot of documentation, definition, and cost with it, so the FAA and ICAO adopted the APV definition, so they could build new approaches and not be burdened with the cost and paperwork.There is a very good explanation with additional detail at this link: https://www.boldmethod.com/learn-to-fly/navigation/what-is-the-difference-between-lpv-and-lnav-vnav-gps-approaches/
9. Unlike TSO-C129 avionics, which were certified as a supplement to other means of navigation, WAAS avionics are evaluated without reliance on other navigation systems. As such, installation of WAAS avionics does not require the aircraft to have other equipment appropriate to the route to be flown. (See paragraph 1-1-17 d for more information on equipment requirements.)
- (a) Pilots with WAAS receivers may flight plan to use any instrument approach procedure authorized for use with their WAAS avionics as the planned approach at a required alternate, with the following restrictions. When using WAAS at an alternate airport, flight planning must be based on flying the RNAV (GPS) LNAV or circling minima line, or minima on a GPS approach procedure, or conventional approach procedure with “or GPS” in the title. Code of Federal Regulation (CFR) Part 91 non-precision weather requirements must be used for planning. Upon arrival at an alternate, when the WAAS navigation system indicates that LNAV/VNAV or LPV service is available, then vertical guidance may be used to complete the approach using the displayed level of service.