Conference expansion has been coming for a long time. TV contracts from the last round of expansion are nearing completion and Texas and OU rumors of jumping to the SEC are likely going to set off the next round. So the question is what do you want the B1G to do? Try to keep it realistic so this isnt just a silly conversation and panicking over the SEC.

Here are some of the most realistic options

• Nothing-The B1G is in a great position and making a lot of money. The Big 12 dying will guarantee multiple B1G schools make the playoffs every year. No candidates who would increase the average revenue per school want to join so no reason to expand. 
• Virginia & North Carolina-The B1G follows the $$ and grabs the biggest state schools in the states of Virginia and North Carolina. VA, NC, PA, NJ, and MD make a really strong east coast group and the B1G now has a really strong east coast stronghold. The difficulty would be convincing those two to leave their instate schools/rivals and breaking the ACC grant of rights deal. Probably unrealistic.
• Notre Dame & Kansas- ND sees the super conferences forming and makes a decision to join the conference that makes the most sense while there is still room. The midwest football powers are finally in one conference and a "North vs South" rivalry will really form between the B1G and SEC. With the Big 12 dying Kansas gets saved and brings a fantastic basketball program over. With most big 12 schools going G5 Kansas will have a really solid opportunity to improve in football.
• Oklahoma & Kansas-Kansas still joins for all of the reasons stated above. But the B1G is able to knock some sense into OU that they may have a bit more fun in the B1G. Why compete against a crowded SEC when they can come and dominate the B1G west and make the same amount of money? Make the playoffs every year, reunite with Nebraska, form a fun rivalry with OSU. Why would you join the SEC instead of that? 
• Texas & Texas Tech- Texas tries to jump to the SEC but complications with A&M, the longhorn network, and OU + OK State make it impossible and the SEC just takes OU & OK State. Texas decides they never wanted to join the SEC and want to come to the B1G with fellow state school Texas Tech. This makes more sense than staying in a dying conference. Texas, Texas Tech, Iowa, Nebraska, Illinois, Wisconsin, Minnesota, and North Western make a nice western half of the conference that can rely on Texas for recruiting now that the Big 12 dissolved. Texas can steal OU's old rival in Nebraska while making as much money as A&M.