Tolkien’s faith is evident in the way he sets up his world. There is a creator deity who cares about his world. However, this is rarely mentioned. There are prophecies and dreams through which the deity communicates to the characters. In particular, the deity works through the small and humble, rather than the powerful, to accomplish his aims. The world is dark, but there is clearly hope.
In contrast, Lewis’s Narnia tales have a deity so real you can see, touch and smell him. Aslan is such an effective portrayal of Jesus (our bridge to the Father) that he has been mentioned in plenty of sermons I have heard over the years.