Pressure should help Lenoir and the secondary The defense has easily been the best unit on the 49ers through the season’s first three weeks. And while they did give up 19 points to Chicago in Week 1, the defense was only responsible for allowing nine points over the last two weeks. Now comes their toughest test in Sean McVay and the Rams offense led by Matthew Stafford and Cooper Kupp. Here at the five 49ers to watch on defense as they try to help the 49ers start 2-0 against the NFC West: DE Nick Bosa Bosa continued his torrid start…