YES, you can! Just as you were able to do in the past with Create Space.
Lightning Source is non-exclusive. You can set up your book on your Lightning Source account and sell it through our global distribution network, or you can use other printers, distributors, fulfillment services, or any companies you choose to work with.
It is our understanding that the KDP program, only allows you to use their Expanded Distribution through Amazon, as long as your book's ISBN has not been previously submitted for distribution through another service such as Lightning Source's distribution network.
If you want to use both Lightning Source and Amazon KDP, just be sure you don’t select the Expanded Distribution service they offer.