Hi Olunkule,
I am not aware of another free source of nationwide wind resource data with more recent data than the WIND Toolkit. If you find data from another source, you can use a spreadsheet program or text editor to create files in SAM's SRW format. See SAM's Help system for a description of the format, or download the PDF here:
sam.nrel.gov/weather-data/weather-data-publications
You are correct that the solar resource data from the NSRDB include wind speed and other meteorological data, but this data is not suitable for wind power modeling because the wind speed data is not measured at or near typical turbine hub heights. For example, the wind speed data is at 2 meters, the approximate height of a ground-mounted photovoltaic array, but much lower than the typical hub height of a modern wind turbine.
Best regards,
Paul.