Manuel Pellegrini was sacked by West Ham following the 2-1 home defeat to Leicester City on Saturday, and Moyes will be hoping for the perfect start against fellow strugglers Bournemouth on Wednesday.
Pellegrini's dismissal did not come as much of a surprise when considering West Ham's form during the 2019-20 campaign. Indeed, the Hammers are currently 17th in the Premier League table, just one point clear of the relegation zone heading into Wednesday's fixtures.
Granted, the capital side have a game in hand on every other team in the division aside from leaders Liverpool, but just five wins from 19 outings this season saw Pellegrini shown the door.
There was not too much widespread speculation in the immediate aftermath when it came to a replacement, with Moyes quickly emerging as the favourite. The Scot was confirmed as head coach at the weekend, returning to the London Stadium just 18 months after being overlooked for the permanent role.
The former Manchester United manager has taken charge of a team that has won just one of their last five in the Premier League, suffering four defeats in the process.
Indeed, they have lost to Crystal Palace and Leicester in their last two and are without a home success in the league since beating Man United on September 22. The Hammers have lost their last four league games at the London Stadium, meanwhile, which will be a concern heading into the New Year's Day fixture.
Bournemouth will not be in the mood to hand out any favours to Moyes on his return, though, considering that the Cherries are currently sitting at the wrong end of the Premier League table.
Indeed, Eddie Howe's team are just one point ahead of West Ham in 16th position having won five, drawn five and lost 10 of their 20 league matches during the 2019-20 campaign.
Bournemouth's last two Premier League wins have been against Man United and Chelsea, recording a 1-0 victory over the latter on December 14 to end a poor run of results.
A fairly substantial injury list has not helped Howe's side this season, but there is no downplaying the importance of this match with both teams looking for what would be three huge points.
West Ham United Premier League form: WLLWLL
Bournemouth Premier League form: LLWLDL
As for Bournemouth, Nathan Ake, Adam Smith, Simon Francis, Charlie Daniels, David Brooks and Lloyd Kelly are all still on the sidelines, but Jack Stacey and Joshua King should shake off knocks to start.
Dominic Solanke could also keep his spot if King fails to recover from a slight injury, but the former Liverpool striker is still yet to score in 29 appearances for the Cherries in all competitions.
West Ham United possible starting lineup:
Fabianski; Fredericks, Diop, Balbuena, Masuaku; Rice, Noble; Anderson, Lanzini, Antonio; Haller
Bournemouth possible starting lineup:
Ramsdale; Stacey, S Cook, Mepham, Rico; Fraser, Billing, Cook, Stanislas; C Wilson, King
We say: West Ham United 2-1 Bournemouth
It is difficult to call this match a relegation six-pointer, but there is no getting away from the fact that it is a huge clash for both teams. Bournemouth are capable of harming the Hammers, but we expect the hosts to shade an extremely close match at the London Stadium.