He lied. I went to Morningstar to look at Amazon's financial data. Clicking on "All Financial Data" here reveals the relevant numbers:
Income before taxes $11,261 million
Net income $10,073 million
Provision for income taxes $1,197 million
Cash paid for income taxes $1,429 million
The provision for income taxes is a GAAP (Generally Accepted Accounting Principles) accrual amount which includes adjusting for deferred or prepaid taxes. However, cash paid for income taxes is obviously cash paid. 1429/11261 = 0.127, or 12.7%. That is not as much as one might expect based on the 21% corporate rate, but it is nowhere near Bernie's lie that Amazon paid zero taxes.
Bernie very likely lied about Netflix, too. Morningstar showed a $15 million provision for income taxes (on pretax income of $1,226 million), but did not show the amount of cash paid for income taxes. Anyway, from the story linked above: "A Netflix spokeswoman said in an email that it is "inaccurate to say that we paid $0 in federal income taxes in the U.S. in 2018"."