Nigel put pen to paper on Wednesday evening and Alan says:
"I have looked at him and chased him for some time now and I just felt he was the right sort of player for this club.
"He is only 19, captain of Wimbledon, has terrific energy, and can make raids into the opposing half all day long so he will be important to us.
"I didn't want to invest the money into an ageing player - I wanted somebody who could possibly bloom into a Premiership player and I honestly believe Nigel can, and I wouldn't bring him in if I didn't.
"And I hope it is not too early to take him for a club like us and have to play him.
"I think the other clubs that were looking at him would have taken him to the Premiership and probably bedded him in but we can't afford to do that.
"He will go straight in and with the midfield players we have got now I feel we are much, much stronger than we have ever been since I have been here."
Other clubs were interested in Nigel but it was Alan that took the plunge, and he says:
"It is important that you back your judgment; there were a few that went to see him but I can't speak about why they didn't go and get him.
"There were two or three in the chase but we managed to secure his services and of course one of the big attractions is to play for West Ham United - you can't get away from that.
"He wanted to come to us and I think that was a big factor in it - he is a London boy and he knows the importance of West Ham."
Alan feels that Nigel can make a huge contribution this season and he adds:
"I kept thinking that if we lost Hayden to injury or something we would struggle for energy in that midfield, so it was important that I got another player of his ilk.
"But he also has his own special qualities - he brings leadership qualities to the team, which sounds strange for a 19 year old, but he does."
As for erstwhile Dons colleague Adam Nowland, Alan adds:
"He should be secured in the next 36 hours or whatever; he has come as part of the deal."
Alan admits that Adam has to go through a steep learning curve to be a success at Upton Park and adds:
"He is not so definite; there is a challenge in front of him and it is a big step up for him.
"I have taken him because I just have a feeling for him; he will come into the squad and we will see how he progresses.
"He is a natural footballer, a West Ham type of player; he has got great flair and he is a great passer.
"It is only just recently that he has dropped back into central areas.
"He was a bit of a wonderkid when he was younger as a striker, and it never really materialised for him for whatever reason.
"He has gone back into central midfield and has been absolutely brilliant in the last 10 or 15 games for Wimbledon.
"Most clubs would have waited for him to get a few more games under his belt but he just caught my eye, he gave us the runaround in the reserves - and I feel he will be just right for West Ham.
"There are some sides of his character that he needs to work on and I have stressed that to him.
"This lad is a bit of a maverick but you have to have mavericks in your team if you are going to win things.
"I am hoping to secure him soon and we will see how he progresses.
"I am excited about them both and with them joining the young players we have got like Carrick, Mullins, Etherington, it all bodes well."