The prior answers aren't complete, and the omitted rules tend to favor an election under 179. So the poster really should consider a 179 election, if one's available.
Assuming the leasehold improvements are eligible for 179 expensing, the limitation on any deduction is taxable income from *any* active trade or business, including employment. So you'd want to look for $100k of taxable income from *all* such business activities, including W-2 wages, not just from the restaurant franchise.
Also, any excess that's not allowed in the first year is carried forward for use in future years. So the hypothetical deduction of $100k offsets the next $100k of taxable income from a T or B, whether earned this year or in future years. If you're not limited under 179(b)(1) and (2), the standard advice is to consider a 179 election even if there's no immediate tax benefit. This outcome is better than depreciation over a longer schedule, or even 168(k) expensing (assuming a legislative fix, which seems unlikely), since 179 is immediate and the carryforward is not subject to the limitations of 172.
