According to the specification, the M2_2 slot accepts SATA SSD:
1 x M.2 Socket (M2_2), supports M Key type 2230/2242/2260/2280/22110 M.2 SATA3 6.0 Gb/s module and M.2 PCI Express module up to Gen3 x2 (16 Gb/s)**.
M2_1 from your board only takes NVME.
However, the WD Green has no DRAM cache and 128 GB is also quite low. Depending on the intended use, I would recommend an SSD with at least 256GB and DRAM cache (e.g. WD Blue 3D NAND, Crucial MX500 etc).