Richard Sherman -- Violinist's Business Explodes ... After Online Shout-Out

Richard Sherman is great for business ... 'cause the Vegas street violinist who put on an impromptu show for the Seahawks cornerback tells us he's been getting huge business offers thanks to the NFL star.

As we previously reported ... Sherman was so impressed with the violinist's skills ... he posted a video on Instagram ... where his 1.1 million followers could check it out.

Tony B. -- the 23-year-old street musician -- tells TMZ Sports he didn't get rich from Sherman's tip (though R.S. and Pats CB Brandon Browner gave him $25-a-piece) ... but says the encounter was worth much more.

"I've already got a few bookings," Tony tells us, "I got people inviting me to come play for them at weddings, tropical islands ... it's been crazy."

The best offer so far?