You're misinterpreting "strength of schedule" - that refers to the combined record of every opponent the team has played in the current season; it's nothing to do with how those teams performed last season. Quoting from SB Nation:
Strength of victory is calculated by combining the winning percentages of every opponent a team has beaten. Strength of schedule is similar, but combines the winning percentage of every one of a team's regular season opponents, win or lose.
As both teams have won their only game, their strength of victory and strength of schedule are identical. However, the next tiebreaker is now
- Best combined ranking among conference teams in points scored and points allowed.
As the Chiefs beat the Patriots 42-27 they have a +15 ranking while the Raiders have a +10 ranking from beating the Titans 26-16, so I think the Chiefs should still be ranked higher than the Raiders. (Also, the Broncos should be ranked even lower, having won only 24-21).
I personally suspect the algorithms being used for generating the on-line standings just don't go that far down the tiebreaker procedures; I don't believe anything later than strength of victory has ever actually been needed.