Just unplug your HDD/SSD and connect one stick with live version and one stick with nothing important you want to save then install like you could install to HDD/SSD and after installing linux lite plug your HDD/SSD back. This will overwrite all data on the second stick!
After installing linux lite to the second stick you can format the first one and use it to your needs
After installing linux lite to the second stick you can format the first one and use it to your needs