A tale of two Nanas
I have a daughter who is 14 and is not my husband's biological daughter, and we also have a 4-year-old together. My children call my mother Nana and my oldest has done so even before my husband and I met.
My oldest and my mother are very close. We lived with my parents until she was 3.
My husband's sibling's children call his mother Nana as well, and my husband insists that our children call her Nana, too.
My oldest would never call her Nana out of respect for her Nana (my mother). I asked if they could call her something similar, like Nana "Vicki." He said, no way.
My youngest one gets confused because she spends a lot of time with my parents, whereas his parents spend very little time with them, and when he insists on calling his mom Nana she gets confused about who he is talking about and I then have to explain that it's Dad's mom.
Am I justified in feeling they shouldn't have to call her Nana if they don't want to? And how do we remedy the situation?
What, your Nana is better than his Nana so yours wins?
Your husband is being stubborn, yes, but so are you, and you're topping off your stubbornness with bias toward your own family. If anyone has leverage here, he does.