τῷ μιν ἐεισάμενος προσεφώνεε θεῖος ὄνειρος:
The dictionary translates it as ‘having likened itself to him’. but why not ’ having appeared to him?’ Both meanings are there.
It’s the normal use of the middle in Homer, cf. e.g. 2.280 (Athena) ειδομένη κήρυκι or 791 (Iris) είσατο δὲ φθογγὴν υἷι Πριάμοιο. And it wasn’t to Nestor that the dream appeared!