To truly clarify:
Only three cards allow direct transfer to UA MP Miles at a 1:1 ratio:
1. Chase Sapphire Preferred (Personal Credit Card)
2. Chase Ink Plus (Business Credit Card)
3. Chase Ink Bold (Business Charge Card - cannot carry a balance)
However, points from other UR rewards programs can be combined and transferred to UA MP Miles at a 1:1 ratio as long as you have at least one of the three cards above. That means that the following cards can also be added:
1. Chase Freedom (Personal Credit Card)
2. Chase Sapphire (Personal Credit Card)
3. Chase Ink Classic (Business Credit Card)
Good luck.