What does Mila mean?
From the Slavic element mil 'dear, gracious, loving', used as a short form of names like Milena and Ludmila. (A separate Spanish Mila is a short form of Milagros 'miracles'; the love sense is Slavic.)
What does Nadia mean?
A Slavic name derived from Russian/Bulgarian Nadezhda, from Old Slavic for 'hope' (Proto-Slavic root naděja). Originally a diminutive of Nadezhda, it is widely used as a given name in its own right. Note: a separate Arabic name Nadiyyah ('tender, delicate') is sometimes conflated with it but is an unrelated root.