"And [he has] not for anyone any favor to be rewarded," meaning: he does not do that for a favor for which he is to be recompensed by anyone.
﴿وَمَا لأَحَدٍ عِنْدَهُ مِنْ نِعْمَةٍ تجزى﴾ أَيْ: لَيْسَ يَفْعَلُ ذَلِكَ لِنِعْمَةٍ (ل ٣٩٥) يجزى بهَا أحدا