The NAMI information may not be very helpful in identifying the manufacturer, since NAMI is simply a certification program.
With a bit more information about the window, you might be able to use the NAMI website to get the name of the manufacturer.
Here's a list of possible manufacturers and their Manufacturer ID.
Manufacturer Name - Manufacturer ID
A Window Inc. - 412-1
Acadia Windows and Doors - 317-1
All Seasons Window & Door Manufacturing, Inc. - 353-2
All Temp Window Products - 165-1
Alpen HPP, LLC dba Alpen High Performance Products - 1914-1
American Exteriors Mfg. Inc. (Ponderosa) - 591-1
Arlene Stained Glass & Door Co., L.P. - 1672-1
B.F. Rich Company - 292-1
Changshu Hard Glass - 1547-1
Changshu Yili Building Material Company, LTD. - 1689-1
Coastal Industries, Inc. - 1632-1
Columbia Glass & Window Co. - 792-1
Columbia Metal Products Co. (KS) - 790-1
Custom Built Window & Door - 1628-1
Custom Window Systems, Inc. - 629-1
Diamond Windows & Doors - 1633-1
Elixir Industries - Division 34 (TN) - 1773-1
Fen-Tech, Inc. - 354-1
Fene-Tech, Inc. - 1037-1
Fenergic - 1591-1
GlassCraft Door Company - 1157-1
Heartland Window Manufacturing - 1018-1
IDP, Inc. - 1655-1
J & M Glass Company, Inc. - 396-1
Jantek Industries - 347-1
JELD-WEN Custom Doors (IWP) - Ciudad Industrial - 548-1
Jenkins Manufacturing - 1615-1
Kensington HPP, Inc. - 1954-1
LAS Enterprises - 1124-1
Lockheed Window Corporation - 334-1
MariTech Windows - 1477-1
Mathews Brothers Company - 335-1
Mercury Excelum, Inc. - 336-1
Phace LLC dba Accent Windows - 1126-1
PIVA Group spa - 1722-1
Ply Gem Window Group (Alenco - GA) - 162-1
Ply Gem Window Group (OH) - 1411-1
Ply Gem Window Group (VA) - 1408-1
Qinhuangdao ABP, Co. LTD. - 1608-1
Quaker Window Products - 031-1
RSL, Inc. (NJ) - 732-1
RSL, Inc. (OH) - 1436-1
Sain-Gobain Polska Sp z o.o-Lubartow - 1703-1
Saint-Gobain Polska Sp z o.o-Pruszkow - 1704-1
Serious Energy, Inc. - 1437-1
Shanghai Kinghua IG Blinds Company, Ltd. - 1925-1
Shwinco Architectural Products, LLC - 692-1
Silver Line Windows - 1674-1
Star Windows, Inc. - 804-1
Sun-Tek Manufacturing, Inc. - 225-1
Suzhou Taifeng Glass Decoration Co., LTD - 1732-1
Target Windows and Doors, Inc. - 1641-1
Therma-Tru Corp. (Mexico) - 1574-1
Thermal Gard Building Products - 695-1
THV Compozit Windows & Doors - 1578
Tri State Building Materials Corp. - 1626-1
Trulite Window &; Door Solutions, LLC - 1880-1
Vinylmax LLC - 072-1
Vytex Windows - 226-1
West Window Corporation - 113-1
Wincore Window Company, LLC - 1640-1
Window Tech Systems, Inc. - 008-1