I will attempt to provide you with a brief answer.
Since The Magician's Nephew is a sort of refashioning of the Genesis
creation story for Narnia, we can surmise that the main conflict will
be similar to the temptation of Adam. Digory, the "Adam" of this book,
is tempted to get magic apples by the witch Jadis, soon to be The
White Witch, and is told by her that it can heal his ailing mother.
Digory is able to overcome this, unlike Adam, and is able to get his
mother healed by Aslan, the representation of God in this story. The
protagonist's main enemy is not really Jadis the Evil Queen, but with
his own tendency to sin. Ideally a conflict between man and his sinful
I have taken the analysis from notes in these sites:
Narnia Feature Articles: March 2005: The Magician's Nephew complete analysis
BookHooks: Book report on The Magician's Nephew
Into the Wardrobe :: a C. S. Lewis web site
Google Search strategy:
magician's nephew story conflict
I hope this has been a helpful answer. If you need something
clarified, or have a problem with the answer, do please post a Request
for Clarification before rating and I'll come back to you as soon as I
can. Thank you.