I think it is possible. Considering that Egypt had become agricultural 10 - 15,000 years ago, Osiris represents the cycles of the growing season. If you look at that in conjunction with Osiris being a metaphor for the vegetation and Jesus' body the wafer/bread, I believe Osiris could have inspired this. Memorize the prayers in the Book of the Dead so that when your heart is weighed on the scales of Ma'at, you will say the right thing and join Osiris in the reed fields for eternity. But as RLynn says, there are so many dying/rising gods that share this same concept, it is hard to pinpoint this all on Egypt.
Norse: Balder is the son of Odin, was born on Dec 25th and died by his brother's hand who was tricked by Loki. His wife went looking for him, just as Isis went looking for Osiris. When Nanna couldn't find Balder she threw herself on his pyre. Balder represented the light, and Nanna represented the vegetation. No light, no vegetation. This myth has always reminded me of Osiris/Isis and Persephone/Demeter all in one.
Celtic: Lugh was a warrior god of light, and was born on Dec 25th. He had a regenerative cauldron so that his followers would always have food to eat. (Lugh's town - London)
You could also find similarities with Seth killing his brother Osiris, and Osiris' son looking for vengeance... which was known to occur in most patriarchal societies...also to be found in MacBeth and Lion King