Welcome to the forum. Milt Sparks is quoting 20-26 weeks now, and if you want the thin laminated construction of the NLG then you'll have to go with them.
If you're looking for a standard Nelson type holster, there are several good options. I'm a fan of John Ralston at 5 Shot Leather 5 Shot Leather, LLC - Home 5shotleather He makes a great version of the Nelson Professional, both in standard format and with a rear snap loop. Eric at HBE H.B.E. Specialty LeatherWorks has also gotten good reviews for his rendition of that model. Both will probably have shorter delivery times than Sparks.
I'm sure others will chime in with more suggestions for you. Good luck.