See here what I have used to start Node and MxServer as NT Services, hope this helps - JP
PS: Note that your WAS home variable may be different on your machine
1) Node
WASService -add NodeAgent -serverName nodeagent -profilePath "C:\Program Files\IBM\WebSphere\AppServer\profiles\ctgAppSrv01" -wasHome "C:\Program Files\IBM\WebSphere\AppServer\profiles" -logRoot "C:\Program Files\IBM\WebSphere\AppServer\logs\managerprofiles\ctgAppSrv01" -logFile "C:\Program Files\IBM\WebSphere\AppServer\logs\managerprofiles\ctgAppSrv01\startNodeAgent.log" -restart true
2) MxServer
WASService -add MXServer -serverName MXServer -profilePath "C:\Program Files\IBM\WebSphere\AppServer\profiles\ctgAppSrv01" -wasHome "C:\Program Files\IBM\WebSphere\AppServer\profiles" -logRoot "C:\Program Files\IBM\WebSphere\AppServer\logs\managerprofiles\ctgAppSrv01" -logFile "C:\Program Files\IBM\WebSphere\AppServer\logs\managerprofiles\ctgAppSrv01\startServer.log" -restart true