Taxable income and MAGI are two different things. Taxable income (Form 1040 line 15) is your AGI (line 11) minus your standard deduction or itemized deductions (line 12). If your taxable income on Form 1040 line 15 is $156,000, then your AGI must be at least $185,000. MAGI for the Lifetime Learning Credit is AGI plus a few uncommon additions, so your MAGI is your AGI or higher. The MAGI limit for the Lifetime Learning Credit is $180,000, not $190,000, so you are over the limit.