﴿ نُزُلًۭا مِّنْ غَفُورٍۢ رَّحِيمٍۢ ﴾

“as a ready welcome from Him who is much-forgiving, a dispenser of grace!””

as a hospitality a pre-prepared provision nuzulan is in the accusative because of an implied preceding verb ‘appointed for you’ from One Forgiving Merciful’ namely God.