In early June 1880, he came within 75 votes of receiving the nomination at the longest ever Republican convention in Chicago. Although his two terms had been lackluster, the 'stalwart' faction backed Grant, probably because they sought a prominent standard bearer/figurehead. OTL many of the larger state delegations split rather than endorsing him en bloc, but had they given unanimous support he could have approached the requisite 379 delegates. If he came very close,the powers that be might have swung the modicum of votes his way after a few more ballots.
The Democratic convention was due in two weeks and I doubt they would nominate Winfield Scott Hancock as per OTL.
In view of the close, bitterly-contested nature of Gilded-age US presidential elections (particularly 1876), and Grant's poor record in office, would he have won if nominated in 1880?