If I am a resident of Indiana, but I didn't work there in 2023, and I worked in 2 other states, why did I only get a tax credit for one state, not both that I worked in?

Make sure that you only allocated income earned in CA to the CA return, and only CO income was allocated to the CO return.   Your resident state (IN) will tax all of your income.   The tax liability to CA and CO can be credited to your IN return.   You can find your tax liability on your CA and CO nonresident tax returns:

CA 540 NR - Line 74

CO Form 104 - Line 11

From the IN Dept of Revenue regarding this credit (you can enter this credit at the end of the IN state interview in TurboTax):

Details
Indiana residents must report all income that is reported for federal income tax purposes on their Indiana individual income tax return. This includes income from sources outside Indiana. Likewise, nonresidents who receive income from Indiana generally will owe tax to Indiana on the part of their income that is from or connected with Indiana sources.

When this happens, individuals may be subject to individual income tax by both their state of residence and the state where the income comes from. Indiana has entered into agreements with several states to eliminate the requirement of paying tax to two states on the same income.  Tax treatment of out-of-state income depends upon the types of income and the state from which the income is derived.

Note: Indiana only allows credits for individual income tax paid to other states or localities. Other taxes such as property taxes, corporate income taxes, and unincorporated business taxes are not allowed as a basis for claiming such credits.

Who is Eligible?
Certain individuals who receive income from other states.

Additional Forms
Schedule 6, Schedule G

Group A Worksheet IT-40 booklet/IT-40PNR Federal Form 1116; other state tax return