How to reset a 4026 counter IC when it reaches 6 for electronic dice
The counter, i.e. 4026, that you specify is a device already containing the 7-segment decoder. Plus this counter is not really suitable to the application where you want it to count from 1 through 6. 

Instead look at using a counter such as a 74HC161. This can be hooked up as shown below to make it count from 1 through 6.



This circuit will count from up to 6 (i.e. the state where QB and QC both come to 1's in the output count. The 74HC00 NAND gate will detect this condition and force the synchronous LOAD input active low. On the next clock pulse from the 555 chip the counter will reload to a value of 1 (Inputs D C B A in the 0001 binary state) as opposed to advancing to a count of 7. Subsequent clocks will then count 1->2, 2->3, 3->4, 4->5, and 5->6 where the reload cycle will repeat itself.

Note that at initial power up this circuit may have an initial value in QD QC QB and QA that is outside of the range of 1->6. If this happens it is just necessary to let the clock run till the counter advances to a state where QB and QC are both 1's. If this behaviour is unacceptable then is is necessary to design in an additional signal that low ORs in with the output of the NAND gate to initially force the counter LOAD Input low for one or more clocks from the 555.