Hi there,
SO the Nords list this in the latest info, addressing the Battery power and a couple thread scenerio’s,
Battey lifetime
Let’s consider the battery lifetime of a coin cell battery, specifically CR2032), with a nominal capacity of 225 mAh.
Bluetooth LE advertising
A Bluetooth LE beacon operates by advertising at 0 dBm every 10 seconds. It carries a payload of 31 Bytes, which is the maximum payload for an advertising packet with legacy advertising. With an average consumption of 3.8 µA, the battery can last for over 6 years.
Bluetooth LE connection
Let’s consider a scenario, in which you have a device connected to a central unit with a connection interval of 4 seconds. This setup would decrease the battery lifetime to 5 years and 4 months.
If you’re curious about the power consumption of your specific configuration, see the Online Power Profiler. It allows you to enter your connection settings and will estimate the power consumption for that connection.
Matter over Thread
Let’s consider a device running Matter over Thread on the nRF54L Series. With short idle time (SIT) and default configurations, the battery lifetime extends to 1 year and 7 months. This duration is 4 months longer compared to using the nRF52840 SoC.
In long idle time (LIT), the battery lifetime is over 6 years.
SO keep in mind this is the Silicon Package itself, the Xiao design envelope may add additional overhead, which we all know it does.
either through restrictions or requirements 
to me the takeaway is the 225 mAh, I like the slightly thicker but more robust CR2450 Approximately 550 to 620 mAh, depending on the brand. (11 years) 
HTH
GL 
PJ 