WASHINGTON, Feb 15 (Reuters) - A top Republican lawmaker has challenged the widely respected congressional forecaster on budget issues, the Congressional Budget Office, accusing it of a slanted report on taxing corporate profits, according to documents released on Friday. A 36-page January CBO report concluded that tens of billions of dollars in new government revenue could be raised over a decade by limiting corporations' ability to defer taxes on foreign profits, a tax change favored by President Barack Obama.