You can access historical monthly nodal power price data using both Lens and Lens Direct:
In Lens
Use this pre-filtered view: Historic Nodal Pricing β Lens
Go to the Power Price by Settlement table
Select "Market historical" to view the monthly nodal price trends
Use the time slider to focus on your period of interest
Toggle to data table view and export to Excel if needed
In Lens Direct
The same data is available and can be accessed by querying the appropriate tables, many users find the chart view in the Lens UI more intuitive for spotting trends.
The following view in Lens Direct provides the required data: