The power description for "Welcome to my reality" reads:
Scarlet Witch restructures the world to her will. Choose a tile. This power becomes Chaos Magic. Its color is the chosen tile's color.
However, when choosing a tile it does not let you pick anything other than a basic tile. No web/charged/character/special tiles.
I will admit that it's not super common, but there are matches where this is may be problematic (heavy enemy tile or web tile spam for example).
Either the power description should specify "Choose a colored basic tile" or (my preferred option ) it should let you pick nonbasic tiles too.
This has always bugged me. It is not a power that is modifying anything on the current board state. The tile choice is there just for later turns so why it doesn't allow special tile choice makes no sense. There is the odd time with special tile spammers that it can make a difference.
It was perhaps easier to code to only basic tile and I assume the thinking is with only a 3 AP cost, it would be fired early in a match there will always be a basic tile of each colour available.
Having to choose a tile also prevents you from choosing a color that is not on the board.