Noble made it 1-0 a minute into the second half when his 40-yard free-kick evaded all in the box and past Saints keeper Artur Boruc before skipper Nolan tapped home at the back post after some good work by Yossi Benayoun.
Just after the hour-mark, Adam Lallana gave the visitors some hope when he volleyed home past Jussi Jaaskelainen but sanity in East London was soon restored when Jose Fonte handled in the area under pressure from Andy Carroll with referee Neil Swarbrick pointing to the spot.
Nolan stepped up and fired home to make it 3-1 before summer signing Maiga wrapped up proceedings three minutes from time with a left-footed curler.
The Hammers replaced London rivals Tottenham in fifth place with their fourth win of the campaign but it is a different story for fellow promotion-winners Southampton who are 18th following their sixth defeat.
Upton Park, London - 34,925